Switch operating means



July 14,1959 1 J. M. RODGERS ET AL 2,

, SWITCH OPERATING MEANS Filed April 26, 1957 3 Sheets-Sheet 1 INVEN'ILORS JOSEPH M. RODGERS ROBERT w. LELAND THEIR-ATTORNEY July 14, 1959 J. M. RODGERS ET AL 2,395,026

' SWITCH OPERATING MEANS Filed April 26, 1957 s Sheets-Sheet 2 THEIR ATTORNEY v x M Q J. M. RODGERS ETAL SWITCH OPERATING MEANS July 14, 1959 Filed April 26, 1957 3 Sheets-Sheet 3 ARMATURE TRAVEL '5 VII wzmur ,v'" w I I I I I OUT TOUCH SEAL ARMATURE TRAVEL CONTROLLER WITHOUT EXTERNAL SPRING MEANS 7" 'mTAL 1 r 1?. i? wig a CM!!- 3 lfl E a; 7' com smma COIL FORCE I wzwnr K I I our TOUCH .9541.

ARMATURE TRAVEL I80 v., 1 I7; 16 WITH TOGLE .CPRINB! I V SKETCH FOR 1 '1 i, 220K RATED COIL 9' Q a, I i "w r z 490 H D Q I op II m k H wnn 706812 suave: 7 90 4m 8 001720 L-nvss: Ber 0;: Ann/n0 roau: smnvcs i i 1 OUT .TOUCH SEAL THE/R AT OKNEY .able motor-starting-controller armature United States Patent SWITCH OPERATING MEANS Joseph M. Rodgers and Robert W. Leland, Dayton, Ohio, assignors to General Motors Corporation, Detroit, Mich., a corporation of Delaware Application April 26, 1957, Serial No. 655,386

9 Claims. (Cl. 200-87) This invention relates to an operating means for a motor starting controller.

An object of the invention is to provide a switch operating means capable of effectively opening and closing electrical contacts adjacent each other and concurrently eliminating both contact-damaging chattering and/or arcing of current.

Another object of the invention is to provide a motor starting controller having operating means for making and breaking electrical contacts through movement by an armature of an electromagnet positively to close contacts to seal position fully at slightly above minimum electromagnetic actuating voltage and positively to open contacts fully at slightly below minimum electromagnetic actuating voltage to eliminate a contact touch position encountered in opening and closing contact for a time interval during which damaging chattering and arcing previously could occur A further object of the invention is to provide a motor starting controller having toggle spring means attached thereto relative an armature of an electromagnet for positively permitting travel of the armature to opposite ends of possible shifting movement thereof completely to open or to close electrical contacts near minimum electromagnetic operating voltage.

Still another object of the invention is to provide a motor starting controller with an electromagnetically movable contact-carrying armature having a spring hanger attached thereto pivotally engaged by a coiled toggle spring means rendering progressively less force relative to armature movement to a contact closing position and progressively greater force urging contact breaking to complete open contact position.

Another object is to provide a multiple contact motor starting controller operated by an electromagnetically movable armature subject to force from a toggle spring means assuring positive contact engagement at and above minimum electromagnetic operating voltage and positive complete contact separation below minimum electromagnetic operating voltage.

It is also an object of the invention to provide a toggle spring operating means for an electromagnetically mov including a bracket on a base, a bearing means carried by the bracket, an armature-carried hanger with a central bearing portion and a pair of coiled toggle springs having inter-locking ends pivotally engageable about the central bearing portion of the hanger and having the ends remote from the hanger for each engaging the bearing means.

Another object of the invention is to provide a motor starting controller including an electromagnet and armature or reciprocable contact carrier for movable contacts spring urged into cooperation with stationary contacts under like pressure, but tending to remain in touch position relative each other except for electromagnet force overcoming (1) armature weight, (2) the spring urging force, and (3) a decreasing toggle spring force to close contacts to a full sealposition at or above minimumelcctromagnet actuating voltage; and, except for positive force from toggle springs urging complete contact separation away from, but not including contact seal position right through touch position to open position below minimum electromagnetic actuating voltage, due to the same spring urging toward touch position whereby the toggle springs are moved away from a position of minimum or zero force applied at contact seal position to an increasing force and the toggle springs are applying movement carrying the armature with the movable contacts to a fully open contact position whenever the electromagnet receives below-minimum actuating voltage to eliminate chattering or arcing of current across the contacts.

Further objects and advantages of the present invention will be apparent from the following description, reference ferred embodiment of the present invention is clearly shown.

In the drawings:

Figure 1 is a partially sectioned side elevational View of a motor controller incorporating features of this invention.

Figure 2 is a plan view of the controller illustrated in Fig. 1 with a cover partially broken away to show electrical contacts in a fully open position.

Figure 3 is a fragmentary view like Fig. 2 to show electrical contacts partially sectioned in a fully closed or seal position.

Figure 4 is an end view of the controller of Fig. 1.

Figure 5 is a side view of bearing means used with a toggle spring assembly on the controller of this invention.

Figure 6 is an end view of a hanger used with the toggle spring assembly of this invention.

Figure 7 is a side view of the hanger of Fig. 6.

Figure 8 is a perspective view of a bracket used with the toggle spring assembly of this invention.

Figure 9 is a plan view of a coiled toggle spring in a compressed condition used with this invention.

Figure 10 is an end view of the spring of Fig. 9.

Figure 11 is a plan view of the spring in Fig. 9 in a fully released and uncompressed condition.

Figure 12 is an end view of the spring of Fig. 11.

Figures 13, 14, and 15 are graphs illustrating and comparting effects upon voltage characteristics on contact opening and closing with a motor starting controller with and without using the present invention.

With particular reference to Fig. 1 the motor starting controller using the present invention comprises a base 20 on which there is mounted a support 22 for a plurality of stacked laminations 24 forming upon an electromagnet generally indicated by the numeral 26 having an armature 28 reciprocable thereby. The base also carries an insulating means generally indicated by numeral 30 which is adapted to be cooperable with a cover 32 also made of insulating material. The insulating means 30 is formed with a plurality of transverse insulating walls 34 which divide space enclosed by the insulating means and cover into a plurality of compartments isolated from each other to prevent arcing or shorting of electrical current from one compartment to another with the motor controller of the present invention. Each compartment 36 contains a fixed contact 38 having an electrical surface 40 covered with material such as silver. The fixed contact 38 can be suitably attached to the insulating means by a screw 42 which serves to hold contact 38 in electrical engagement with a terminal 44 shown only partially in the cross section of Fig. 1, but shown fully with the unsectioned portions of Fig. 1. This terminal 44 is adapted to receive a conductor for connecting various electrical devices into an electrical circuit for which the subject motor controller can be used. The fixed contact 38 is so disposed in the compartment 36 to be engageable by a movable contact 48 which is carried by a carrier portion 50 attached to armature 28 of the electromagnet 26 which is energized by a coil 27 visible in Fig. 3. It is to be'understood that the electromagnet is provided with a coil structure having details as outlined in a copending patent application S. N. 404,843, David F. Moyer, filed January 19, 1954, disclosing a circuit breaker. The basic structural arrangement of the fixed and movable contacts together with the electromagnet, armature and contact carrier as described in this copending application is the same as is used with the present invention wherein a switch operating means including a toggle spring assembly generally indicated by the numeral 60 is combined with the motor controller.

Figure 2 is a plan View of the motor controller of Fig. 1 including the toggle spring assembly 60. The partially broken away view of cover 32 illustrates structural arrangement of carrier 58 linearly reciprocable relative to walls 34 of insulating means 38 whereby fixed contact 38 is engageable by movable contacts 48, whenever the electromagnet 26 is energized with sufficient operating voltage to cause movement of armature 28 sliding carrier 58 to contact closing position. The controller of the present invention and also that disclosed in the above mentioned copending application is generally mounted in a vertical position wherein the toggle spring assembly as provided in the present invention is located at the bottom and the reciprocal movement of armature 28 and carrier portion 50 is up and down in a vertical line of movement. Thus, to operate the controller for closing contacts 38-48 disposed in each compartment 36, it is necessary for an actuating voltage to be supplied to a coil of the electromagnet 26 with sulficient magnitude to overcome the total weight of the armature, carrier and contacts 48. Because of the possibility of slight misalignment of fixed contacts 48, a contact spring 2 is provided with the movable contact 48 as shown by the fragmentary cross section of Fig. l and a fragmentary cross section of Fig. 3 which shows a cross arm 64 on which the movable contact arms 48 are provided. The contact spring 62 is disposed between a central portion 66 of the cross arm 64 and a wall 68 of a slot 78' provided with the carrier portion 50. unevenness between fixed contacts 38 and movable contacts 48 is resiliently compensated by the contact spring 62 whenever carrier portion 50 is shifted to a contact closed position by electromagnet 26. The contact springs 62 are necessarily compressed slightly when the carrier is moved to a position representing a completely closed or seal contact position. Figures 1 and 2 show the contacts in the fully open position and Fig. 3 shows the contacts in a fully closed, home, or seal position. To represent an improvement achieved with the present invention, Fig. 3 also shows a phantom representation of wall 68 as wall 68' with the carrier 50 at which contact spring 62 would be in an approximately uncompressed condition relative to central portion 66 and wall 68' in the subject controller. This phantom position is also indicated in Fig. 3 by a phantom representation 28' of the armature 28 movable by electromagnet 26. The phantom position represents what may be referred to as a contact touch position wherein the movable contacts 48 are not solidly in engagement with the fixed contacts 38 so that chattering or electric current arcing may occur across the contacts, This chattering or arcing may result in a pitting, melting of the silver with the current arcing, or other damage causing rapid dethe curent arcing, or other damage causing rapid deterioration and failure of the motor controller when used in an electrical circuit. The open position of the contacts as represented in Figures 1 and 2 is not attained in the controllerso long as a minimum operating voltage is supplied to the electromagnet 26 sufiicient to barely overcome the force of weights connected with Thus, any

the movable armature 28. As indicated above this force includes the weight of the movable contacts 48 and carrier portion 50 because the armature 28 is attached to the carrier portion 50 by a fitting 72 shown in Fig. 2 of the drawings and described further in detail in the copending application. The touch position mentioned above represents a condition at which the contacts 38 and 48 first make or are about to break electrical contacting engagement with each other. The seal or home position as shown in Fig. 3 represents a condition at which the armature has come all the way home to complete its upward travel vertically depending upon the mounting position to positive and full contact closing position. A voltage somewhat higher than the minimum operating voltage for the electromagnet 26 will move the fixed contacts to the seal position as shown by Fig. 3. With the controller as described in the copending application, a drop in the voltage supplied to the electromagnet 26 at times will be suficient to permit the Weight connected with the armature to fully separate the contacts 38 and 48 so that no damage can occur to the contact surfaces therewith. However, the present invention is a decided improvement over the contact made by the controller of the copending patent application because the touch position represented by the phantom lines of Fig. 3 is eliminated in effect as a condition at which the contacts can be held for a time interval whenever certain voltage conditions to be described in further detail below prevail with the electromagnet 26.

The toggle spring assembly 60 of the present invention is the improvement in the switch operating means of the present invention combined with the electromagnet 26 and armature 28 for effecting positive operation of the controller directly from complete contact open position to complete contact closed or seal position Whenever minimum operating voltage is supplied or continues to be available to the electromagnet 26. The toggle spring assembly includes a bracket shown in Figures 1, 2 and 3 to be attached by suitable means such as rivets 82 to base 20 together with the support 22 for electromagnet 26. The bracket includes a twisted portion 91 formed to provide a bearing end 86 having an edge 87 parallel to the line of movement permitted for armature 28 and carrier 50 with the structural arrangement of electromagnet 26 and insulating means 30 respectively. This edge 87 is also in line with the rivets 82 securing the bracket to the base 20 as mentioned. The bracket 80 is shown in a perspective view by Fig. 8 and further detail of the bearing end 86 can be seen with Fig. 8. A slot or recess 89 is formed extending inwardly from surface or edge 87 in alignment with an aperture or hole 98 spaced a short distance from the bottom of the recess 89 with the bracket 80. It is adjacent this aperture 98 that a twisted portion 91 of the bracket is formed. A pair of recesses or slots 93 are formed with the bearing end 86 extending transversely of the recess 87 and aperture 98 on bracket 80. Holes 83 shown by Fig. 8 are formed with the bracket 80 for receiving the mounting rivets 82.

Fig. 4 includes an end view of the bracket 88 and indicates how a bearing means or spring clip 94 shown separately in a side view by Fig. 5 is secured relative to bearing end 86 of bracket 80. The clip 94 is generally U-shaped and is provided with a pair of legs 9'6 bent relative away from each other at their ends as shown by Fig. 5 and joined by an intermediate portion 98 with a dip or curve 99 therewith that provides a bearing point as will be described in further detail below. The legs 96 of the clip 94 are snapped into engagement with the bearing end 86 of bracket 8!) by means of slot or re- -cess 89 and aperture 90.

vided adjacent an end of armature 28. The ends 101 are bent toward each other and extend from legs 103 formed with the hanger extending longitudinally in a direction parallel to the lineof movement of armature 28 and carrier portion 50 with the controller. The legs 103 can be seen in a side view of Fig. 7 and Fig. l as well as in the plan view of Fig. 2. The hanger 100 is shown in Fig. 6 having a substantially S-shaped configuration including an intermediate portion 104 connected by a transverse portion 105-and slanting portions 106 to the legs 103. The intermediate portion 104 is bent to lie parallel to a line or axis defined by ends 101 which pivotally engage armature 28 at holes or recesses 102. The S-shaped configuration is provided by portions 105 and 106 but is interrupted by intermediate portions 104 as indicated by Fig. 6. The intermediate portion 104 provides bearing points for engagement of spring means generally indicated by numeral 110 in Figures 14 of the drawings.

The spring means 110 form part of the toggle spring assembly 60 and specifically comprise a pair of toggle springs 112 fitted between bearing means 94 and bracket 100. Each toggle spring 112 includes a coil or loop portion 114 bent over itself [as indicated in Figures 1, 4 and 12. Two or more loops can be provided in this coiled portion 114 depending upon the resiliency desired with the particular toggle spring. Each toggle spring includes a long leg portion 116 and a short leg portion 118 terminating in a bearing hook 120 and 122 respec tively. These hooks are formed by bending the spring: wire forming the toggle spring into a semi-circular shape as illustrated in Figures 2, 3, 9 and 11. Hook portion 122 is formed coplanar with short leg portion 118 of each toggle spring 112. This can be seen in Fig. 12 of the drawings. However, due to structural arrange-- ment of the toggle spring assembly in the present inven-- tion, hook portion 120 is connected to long leg portion 116 by means of a transverse arm 126 providing a length of spring wire corresponding to the length covered by the coil portion 114 of each toggle spring to return. hook portion 120 into coplanar relationship with hook portion 122 and leg 118. Thus the hook portion 120 and 122 are formed with semi-circular structure lying in the same plane because the transverse portion 126 compensates for the looping height from the coil portion. 114. The purpose of the transverse portion 126 is. specifically to provide coplanar relationship with the hook portions 120 and 122 so that a bearing point is provided by each of these hook portions relative to the bearing means or clip 94 and hanger 100. The bracket 80 and armature 28 are so located with the motor controller that when clip 94 and hanger 100' are attached thereto the bearing points or surfaces pro-- vided relative to toggle spring 112 will all lie within a plane passing through hook portions 120 and 122 as well as intermediate portion 104 and 99 with the hanger 180 and clip 94 respectively. Thus, the force obtained from each toggle spring 112 is transmitted through bearing surfaces lying in a single plane relative to each other acting through hanger 180 between bracket 80 and base: 20 relative to armature 28 and carrier 50 for positive linear movement of contacts 48 relative to contacts- 38 with the controller. Since the force from the toggle springs 112 has no component acting at an angle to the linear reciprocating movement of the armature 28- and carrier portion 50, there can be no twisting or ir-- regular movement of the armature whenever the contactsare moved between open and closed positions. The toggle springs 112 are formed as shown in Figures 11 and 12 when the coil 114 is in a relaxed or uncompressed condition. Figures 9 and represent a substantially compressed relationship of the legs 116 and 118 relative to each other as encountered with the toggle springs 112 assembled as in Figures 1 through 4. The longer legs 116 of each toggle spring 112 form the cornnection between the loop portion 114 relative to the armature 28 as shown in Figures 2, 3 and 4. Each hook portion 120 is fitted against intermediate portion 104 as shown most clearly by Figures 2, 3 and 4. The hook portion 120 of the toggle spring 112 as seen in Fig. 4 extends from transverse portion 126 around intermediate portion 104 of hanger with the end of the hook portion terminating above the end of the other hook portion 120 of the other toggle spring 112. Similarly, the hook portion 120 of the upwardly extending toggle spring engages the intermediate bearing portion 104 of hanger 10d and locks together with or into engagement relative the free end of hook portion 120 of the comparable toggle spring 112 extending downwardly in the end view of Fig. 4. This engagement could be compared in a practical sense with the hooking of index fingers relative to each other except for an intermediate hearing engagement as could be furnished by a rod or pin between the fingers which in the case of the present invention is represented by the intermediate portion 104 of hanger 100 for attachment and transmittal of linear force to armature 28.

The spring assembly 60 including the toggle spring 112 is further completed by engagement of hook portions 122 against intermediate portion 99 of bearing means or clip 94 such that a pivot point provides minimum friction at the tangential contact between an inside surface of hook portion 122 relative to the semi-circular curve thereof against a surface with bearing means 94. It can be clearly seen in Figures 2 and 3 how the hook portions 122 are positioned relative to bearing means 94 and in the movement of springs 112 relative to the bearing means, the hook portion is free to pivot or rotate relative to the bearing means because of cut out portions, slots or grooves 93 formed with the bracket 80. The pivot point of the hook portion 122 relative to hearing means 94 can be seen by Fig. 4 to be coplanar with the pivot connection of hook portions 120 about intermediate portion 104 of hanger 100. The arrangement of the toggle spring 112 on either side of the hanger 100 assures transmittal of equal force from each spring on armature 28 so that, with coplanar arrangement of pivot points, application of force from the springs relative to the movement of armature 28 and carrier 50 is subject to a linear force tending to aid or to hinder and oppose movement of the armature and carrier.

As can be seen in Fig. 3 where contacts 38 and 48 are in a completely closed or seal position, the alignment of bearing points with the toggle spring assembly of the present invention is linear relative to hearing means 94 and the intermediate portion 104 of hanger 100. This linear alignment of these bearing points provides a zero force position for the spring 112 of the toggle spring assembly 60 relative to the armature 28 and carrier 50. As soon as the armature 28 is shifted from this seal position to the equivalent of the touch position represented by the phantom of armature 28 in Fig. 4, due to the contact springs 62 returning to their uncompressed condition, it is to be understood that hanger 100 is shifted a comparable longitudinal distance as represented by the phantom line for armature 28' away from the zero linear relationship of the bearing points in the contact seal position. At this phantom point there is a force from springs 112 to return to a released or uncompressed relation relative to the coil portion 114 with each spring such that an increasing spring force occurs due to springs 112 the further away the armature travels from the fully sealed or home position of the contacts. Conversely, the spring force diminishes from the springs 112 as the armature travels progressively toward a contact seal or home vposition to a minimum or zero value when the linear relationship of bearing means and intermediate portion 104 is reached. Figures 9 and 10 represent the spring 112 when the spring assembly 60 of Fig. 3 is located relative tothe motor controller in a position representing full contact closing. It can be seen in Fig. 10 that the long leg 116 and short leg 118 as joined by coil portion 114 are not in the same plane with each other but that transverse portion 126 serves to position hook portion 120 relative to short leg 118 so that a bearing surface of hook portion 120 for engaging intermediate portion 104 of hanger 109 lies coplanar with leg 118 which is coplanar in turn with hook portion 122.

Summarizing the force applied to the armature 28 and carrier portion 50 in operation of the motor controller, there is necessarily the weight of the armature and carrier portion with the movable contacts and also the force from contact springs 62 which must be overcome by a minimum actuating voltage supplied to the electromagnet 26 for completely closing the contacts 38-48. The graphs illustrated by Figures 13, 14, and represent various force relationship on a controller of the present invention equipped with external spring means such as toggle springs 112 compared with a controller of the same structure as described in copending patent application S.N. 404,843, without the benefit of external spring means. Since the weight of the armature and contact carrier are constant with vertical mounting of the controller, the curves represent resultant force obtained due to additive effects of the weight, the toggle spring plus the weight and the toggle spring plus the contact spring plus the weight. Fig. 13 shows this relationship with a straight line identified by numeral 1349 representing a constant force from these parts opposing the closure of contacts 38-43 with vertical mounting of the controller. A line 132 represents the resultant force of the additive effect of symmetrical located springs 112. As noted above, the force of the toggle springs due to the coplanar relationship of bearing points with the spring assembly 60 provides a diminishing or decreasing force if the armature travels to a fully closed or seal position of the contacts and conversely an increasing force with travel to the outermost or fully open contact position with armature travel. An additional force complicates the curves due to an additive effect opposing contact closure as obtained from each contact spring 62. A dotted line 134 in Fig. 13 represents this contact spring force alone. A summation of forces from the weight line 13b with toggle spring 132 is shown by a line 133 between the outermost position of armature travel to the touch position at which point force from the contact springs must be added to the total force from the toggle springs and weight. To avoid misunderstanding of the meaning of the curves, the force of the contact spring is shown as a dotted line and as the contacts travel to a position approaching a fully closed or seal relationship, the compression of these contact springs 62 increases so that force represented by the dotted line 134 is also increased. The force of the contact springs 62. becomes additive at the touch position to the line representing the total toggle and weight force so that at the touch position force suddenly increases by a vertical component 136 to a point representing armature travel force overcoming the touch position forming a re sultant line of force 138 proceeding abruptly to a fully closed contact or seal position of the contacts with armature travel. The line 138 is more horizontal on the graph Fig. 13 than the line of force 134 representing contact spring pressure or force alone because of the continuing diminishing force effect from the toggle spring line 132 tending to balance off the increasing force from the contact spring line 134.

The graph of Fig. 13 also shows curves representing various forces resulting from energization of the coil of electromagnet 26. Those curves are labeled V, V V V (coil rating). The curves of Fig. 13 translate the voltage into a coil force dependent upon air gap and armature structure relative to the coil. The flux resulting from the energizing voltage supplied from electromagnet 2.6 will vary in a conventional manner according to the air gap and armature characteristics relative to the coil with the electromagnet 26. So long as the minimum actuating voltage V is supplied to the electromagnet 26, the force as represented by the lines in the graph of Fig. 13 will permit the electromagnet to overcome the force of weight, the diminishing force of the toggle springs and also the contact spring force for maintaining contacts 3848 in a fully closed or seal position. This minimum point is located at the juncture of curve V with the line 138 representing the summation of resultant force at the sea] position of the contacts. So long as the voltage remains at this minimum point, there is sufficient coil force from the electromagnet to maintain the contacts in home position. As soon as the voltage drops below this force contact springs 62 will serve to effect movement of the armature and carrier portion toward dynamic touch position represented by the phantom lines of Fig. 3. As noted earlier, this movement toward the phantom position disrupts the zero or dead center relationship of bearing points for transmittal of the diminishing toggle spring force and in effect begins armature movement to an outward or contact open position which cannot be hindered once it is started because of the increasing force from the toggle springs applied at the contact opening movement. Therefore, once the voltage V drops below the minimum actuating holding voltage represented by point 140 on the force curve of Fig. 13, the contacts are not retained in a touch position because increasingly greater forces from each toggle spring 112 are applied to completely separate the contacts 3848 for a clean break eliminating arcing and contact chattering which may damage the contacts to cause controller failure. Once at seal position, so long as the actuating holding voltage supplied to the coil of the electromagnet 26 exceeds the minimum operating voltage, the contacts will remain in closed position, and forces due to voltage exceeding minimum holding voltage V are represented on the graph by curves marked V V and V (coil rating), for example, as applied to the electromagnet. Since the point 140 is below the force at seal position on curves V V and V (coil rating), the contacts remain a fully closed or seal position as long as the approximate minimum operating voltage or more is supplied to the electromagnet 26.

By comparison, Fig. 14 shows the forces from various components resulting in contact operation with a controller of the type disclosed in copending patent applica tion S.N. 404,843 having no external spring means such as toggle spring assembly 60 associated between the base 20 and armature 28 of a motor starting controller. A line 154]: in Fig. 14 represents the constant force due to armature and contact carrier weight obtained with vertical mounting of the controller. At touch position addi tive effect occurs in the force necessary to bring about complete contact closure as force from contact springs as represented by a dotted line 152 is added to the weight line 156 to form a summation represented by line 154. The energizing voltage supplied to the coil of an electromagnet for moving the armature and contact carrier on a controller without toggle springs must be of sufficient magnitude to overcome the increased opposition to contact closure from contact springs such as 62 in the drawings of the present invention. Since there is no decreasing toggle spring force effect, an interval will be encountered whenever an abnormal voltage below curve V of Fig. 14 is applied to the electromagnet during which the contacts such as 3848 will attain and maintain touch position as represented in the phantom structure of Fig. 3 causing arcing of current which may overheat the contact surface resulting in melting of contact material, weld the contacts to each other, destroy and damage insulation and controller structure.

Curve V of Fig. 14 represents force at minimum contact holding voltage and V of Fig. 14 represents force at minimum contact closing actuation voltage. Curves V and V of Fig. 13 for a controller with toggle springs represent force curves corresponding to V and V respectively of Fig. l4-for a controllerwithout toggle springs. Force of curve 'V must exceed force of line 133 to initiate armature movement because of the toggle spring force urging the armature outwardly to contact open position. Force of curve V at out, touch and seal positions is appreciably greater than forces of lines 133, 136 and 138. However, without external toggle spring means as with the controller of Fig. 14 any voltage force exceeding the armature weight force can retain and maintain the armature in touch position until minimum actuating voltage V or holding voltage V are attained. With toggle springs a force is applied to the armature causing movement dynamically through touch to contact open position as motion occurs due to decrease of the actuating voltage to below the minimum seal holding requirement represented by point 140 on the graph in Fig. 13. Using the forces as represented in Fig. 14 for a controller without external spring means, the vertical component 156 of the additive effect of weight and contact spring force occurs at the touch position of armature travel permitting maintained status in the contact touch position so long as. the coil force exceeds the force due to weight alone as represented by line 150.

The meaning of the forces as represented by the graphs of Figures 13 and 14 has been translated into a graph of Fig. 15 for showing voltage relationship between controllers having or not having the external spring means of the present invention. The dotted lines on the graph 15 represent voltage values at which various contact positions are attained when no toggle spring assembly is provided with the controller. The sketch shows the relationship for an electromagnet having a coil rated at approximately 220'volts. Using this rating, an application of 68 volts to the electromagnet coil withbe sufiicient to overcome the force of weight with the vertical mounting of the controller to result in armature travel from the outermostto touch position at which opposition to contact seal occurs due to a force from contact springs such as 62 in the drawings of the present invention. The dotted line with the arrows for movement toward contact closing indicates that a voltage build up is required at the touch position of armature travel from 68 volts to approximately 180 volts before a resulting coil force occurs sufificient to overcome opposition from the contact springs. Thus not until 180 volts is applied will the contacts close to a completely seal or home position with the armature travel. When moving in the opposite direction toward contact open position, a voltage decrease in a source or line supplying power to the coil of the electromagnet could occur to below 135 volts at which point force urging good contact engagement due to contact springs such as 62 was sufiiciently great to cause armature travel representing movement to a contact touch position as represented in phantom with Fig. 3 of the drawings in the present disclosure. So long as the voltage remained above 58 volts, the coil force from the electromagnet transmitted to the armature was sufiicient to retain the contacts in a touch position.

The graph of 15 also shows solid lines representing how contact closing results with the same 220 volt rated coil when the controller of the present invention includes a toggle spring assembly 60 as described above. A line 132 representing downward force due to the toggle springs alone as mentioned with the graph of Fig. 13, also is shown on the graph of Fig. 15. Since this force opposing contact closing increases toward the open contact position, theminimum operating voltage required by the coil of the electromagnet 26 is appreciably greater to initiate armature travel for movement to a contact closed position. Armature travel is opposed by the force from the toggle springs 112 until a voltage of 175 volts is reached approximately and then movement of the armature with the contact carrier occurs with a snap action to move the contacts from a fully open position directly to a fully closed or seal position completely eliminating any delay causing arcing or chattering at the former touch position. The touch position with the controller of the present invention using the toggle springs applying a decreasing force to the zero or dead center position is merely one point in the linear path of travel of the armature which is passed through without lingering or delay. Further, it was found that once the contacts have been closed by a minimum energizing voltage of 175 volts, the spring force of the contact springs 62 together with the resultant force of the toggle springs and weight of the armature and contact carrier has been effectively overcome and the toggle springs force is zero at the fully closed or seal position because of the alignment of bearing surfaces shown by the structure in Fig. 3 described above such that the force of the contact springs 62 and the weight of the armature and contact carrier tending to separate the contacts from a fully seal position is completely counterbalanced by coil force until a voltage drop to approximately 90 volts occurs with the electromagnet coil. At the point Where 90 volts is applied, the contacts still remain in a fully seal position because the minimum actuating voltage still is being applied to the coil of the electromagnet 26. However, as soon as the voltage drops below this minimum operating voltage which may difi'er with various structural relationships of spring forces and armature weights, shift occurs due to the force of contact springs 62 from the dead center or zero force position of the toggle springs 1112. When this shift occurs to the phantom position as represented with Fig. 3 in the drawings disclosing the present invention, the toggle springs exert a progressively increasing force urging complete opening of contacts as represented by the force line 132 in Fig. 15. Thus at approximately 90 volts in the sample tested, the contacts open completely from the seal position of armature travel to the fully open or outward position of armature travel without a delay with the eliminated touch position. Stating the relationship of contact opening and contact closing in another way, it can be said that with the controller of the present invention including toggle spring means 60 disposed between the base 20 and armature 23 of the motor starter controller, there is a deceided difference in the percentages of rated voltage which must necessarily be applied to the coil of the electromagnet for effecting armature travel. Thus the voltage characteristics of a motor controller unit will differ when the present invention is used. The in1- portant positions of the armature travel are the full, out or contact open position, the touch position where the power contacts first make or about to break, and the seal position where the armature has come all the way home to complete its upward travel when the controller is vertically mounted.

When using a controller of the type disclosed in copending patent application S.N. 404,843 Without toggle springs, shift of the armature from the full out position to the touch position occurs at 31% of rated voltage. A movement from the touch position to the seal position occurs at of rated voltage with the contacts re- 'maining at touch position where dangerous arcing and chattering occurs until the voltage supplied to the coil increases from 31% to 80% of rated voltage. Thus, closure of the contacts to a fully seal position occurs at approximately 80% of rated voltage when a controller is used not having the toggle springs of the present invention. On decreasing voltage applied to the coil of the electromagnet due to line voltage variations or any other malfunctions in the source of power supplied to the coil, a movement from the seal position to the touch position occurs at 61% of rated voltage when no toggle springs are provided. A movement from touch position to fullout position occurs at 26% of rated voltage meaning that the contacts linger in a touch position between 61 and 26% of rated voltage. Further voltage characteristics emphasizing the advantages of the present invention over the controller not having toggle springs is realized from tests which showed that the minimum voltage at which at starter controller not having the toggle springs will snap directly from contact open position to a full seal position when voltage is applied instantaneously to the operating coil has to be 66% over the rated voltage of the coil. It is to be noted that the percentages of rated voltage given by way of example with the voltage char acteristics being described are approximate and are not specific due to variations in design of structural relationships of the toggle springs and also the armature and electromagnet structure.

By comparison, the motor starting controller using the switch operating means of the present invention including the toggle spring assembly results in voltage characteristics altered to the following. The armature moves from an open contact or out position directly to a fully closed or seal position at 80% of rated voltage and passes directly through touch position without a time interval delay at this point of travel. Furthermore, the armature drops or moves completely from full sealing position through touch position without hesitation to the full-out position at 43% of rated voltage. The minimum voltage to which the controller will seal completely when voltage is instantaneously applied is 80% of rated voltage for the coil used with the electromagnet.

The addition of the toggle spring mechanism is responsible for the elimination of the hesitation of touch position. This is accomplished by the downward force of the toggle springs in increasing magnitude until a full out or contact open position is attained. However, the contact breaking to open position does not occur until the force of the contact springs 62 shifts the toggle spring assembly to the off dead center position as described above. Sufficient force and momentum is available once the voltage on the coil has dropped to the minimum operating value or below so that at the time touch position is encountered the toggle springs apply a continuously, increasing force and momentum of movement so that no hesitation or stop occurs after touch position. Similarly, in eliminating touch position during decreasing voltage the downward forces of the toggle springs which is increasing from the moment that the armature begins its downward movement from the seal position, serves sufiiciently, along with momentum, to cause the armature to pass through the touch position without hesitation or stop. The toggle spring design represents a spring system of negative rate where maximum downward force is available at the armature in the full out position and zero force is available at the seal position. The latter is a result of design and adjustment such that the toggle system is on dead center at the time the armature is sealed with the contacts fully and completely closed relative to each other.

It can be noted from the example voltage values given above that the decrease in voltage at which the seal position is lost is reduced from 61% to 43%. Thus, in use of a controller embodying the present invention, there will be fewer controller and motor failures due to low and intermediate voltages applied to the controller. With the controller of the present system used in electrical circuits for operation of refrigeration and air conditioning equipment for example, the armature and contact carrier does not drop out from contact sealing position until 43% of rated voltage is applied rather than 61% of rated voltage. The result of this advantage is that the controller remains with the contacts in fully closed or seal position even after the voltage drops to 50% of normal thus permitting functioning of overload relays for protective purposes without chattering and contact arcing with the motor starting control.

While the form of embodiment of the invention as herein disclosed constitutes a preferred form, it is also 12 to be understood that other forms might be adopted a may come within the scope of the claims which follow.

What is claimed is as follows:

1. In combination with an electric starting controller including a base having a plurality of stationary contacts, an el'ectromagnet means carried by said base, a plurality of movable contacts on bars complementary with said stationary contacts, an armature having a movable contact carrier portion therewith shiftable linearly by said electromagnet means, and a toggle spring assembly attached between said base and said armature, said assembly comprising a hanger attached to said armature, hearing means supported by said base on either side of said armature, and a pair of toggle springs fitted between said bearing means and said hanger so that a dead center spring condition exists with zero force exerted by said springs when said movable and stationary contacts are in fully closed seal position relative to each other, said springs exerting increasing force progressively on said armature for movement toward contact open position from zero force at contact seal position and decreasing force continuously from fully open contact position to fully closed contact position permitting complete contact making and breaking at minimum operating voltage values of said electromagnet means thereby eliminating a time interval operational lingering at contact touching position where contact-damaging chatter and current arcing can occur during making and breaking of contacts.

2. In combination with an electric starting controller including a base having a plurality of stationary contacts supported with insulating means thereon, an electromagnet means carried by said base, a plurality of movable contacts on bars complementary with said stationary contacts, an armature having a movable contact carrier portion therewith shiftable linearly by said electromagnet means, and a toggle spring assembly attached between said base and said anmature comprising a pair of brackets attached to said base, a bearing clip fitted to each said bracket near an end thereof, a hanger having an intermediate bearing portion pivotally attached to said arma' ture, and a pair of toggle springs each having a coil loop portion and legs terminating in hook portions at opposite ends thereof, said springs each having one of said hook portions engaging one bearing clip and the other about the intermediate bearing portion of said hanger.

3. In combination with an electric starting controller including a base having a plurality of stationary contacts supported with insulating means on said base, an electromagnet means carried by said base, a plurality of movable contacts on bars complementary with said stationary contacts, an armature having a movable contact carrier portion therewith shiftable linearly by said electromagnet means, and a toggle spring assembly attached between said base and said armature comprising a pair of brackets supported by said base, a substantially U-shaped bearing clip fitted to each said bracket at an end thereof, each said U-shaped clip having a central portion adapted to form a bearing surface, a hanger having a pair of legs parallel to the line of movement of said armature for attachment thereto, an S-shaped portion with an intermediate bearing surface connecting the pair of legs of said hanger adjacent an end of said armature, and a pair of toggle springs each having an intermediate coil portion looped with legs extending therefrom terminating in hook portions at opposite ends thereof, said springs each having one of said hook portions engaging one clip at the central portion bearing surface and the other of said hook portions engaging each other about the intermediate bearing surface on the S-shaped portion of said hanger.

4. In combination with an electric starting controller including a base having a plurality of stationary contacts mounted with insulating means on said base, an electromagnet means carried by said base, a plurality of movable contacts on bars complementary with said stationary contacts, an armature having a movable contact carrier portion therewith shiftable linearly by said electromagnet means, and a toggle spring assembly attached between said base and said armature comprising a pair of brackets supported by said base, a substantially U- shaped bearing clip fitted to each said bracket at an end thereof, each said U-shaped clip having a central portion adapted to form a bearing surface, a hanger having a pair of legs parallel to the line of movement of said armature for attachment thereto, an S-shaped portion with an intermediate bearing surface connecting the pair of legs of said hanger adjacent an end of said armature, and toggle spring means each having hooked opposite end portions, one of said end portions of each of said toggle spring means being engaged against the bearing surface of one said U-shaped clip, the other of said end portions of each of said toggle spring means being interlocked relative to each other about the bearing surface of said shaped portion of said hanger, the interlocking hook portions and bearing surface of said S-shaped portion as well as the bearing surface engaged by said spring means against each said clip lying coplanar relative to each other so that force transmitted by said springs means relative said armature for contact opening and closing is linearly coincident with the linear movement of said armature.

5. An electric starting controller, comprising, in combination, a base, an insulating means forming separate contact chambers on said base, a stationary contact disposed in each of the chambers, an electromagnet means mounted adjacent said insulating means, an armature having a movable contact carrier portion therewith shiftable linearly by said electromagnet means, and a toggle spring assembly mounted adjacent said electromagnet means, said assembly including a hanger attached to an end of said armature, an S-shaped portion with an intermediate bearing surface on said hanger, stationary bearing means located on opposite sides of said armature, and spring means fitted between said stationary bearing means and the intermediate bearing surface of said hanger, said spring means exerting force on said armature in decreasing magnitude with movement to contact seal position Where spring force decreases to zero due to linear relationship of the hanger bearing surface relative to a line between the stationary bearing means, said spring means always exerting an increasing force toward contact fully open position when the position of said armature is other than at contact seal position.

6. An electric starting controller, comprising, in combination, a base, an insulating means forming separate contact chambers on said base, a stationary contact dis posed in each of the chambers, an electromagnet means mounted adjacent said insulating means, an armature having a movable contact carrier portion therewith shiftable linearly by said electromagnet means, and a toggle spring assembly mounted adjacent said electromagnet means, said assembly including means attached to said armature providing a pivotal bearing surface, a pair of stationary bearing means, and a pair of springs each pivotally fitted at one end against said stationary bearing means and at an opposite end to engage each other as well as said pivotal bearing surface of said means attached to said armature, said springs being adapted to apply zero force relative said armature in a position thereof corresponding to 14 fully sealed relationship of the movable and stationary contacts because at this point the ends of the springs pivotally engaged relative to each other are at dead center linearly between the stationary bearing means.

7. The combination of claim 6 wherein points of engagement of the ends of the springs pivotally engaging said stationary bearing means as well as points of engagement of the ends of the springs engaging each other about the pivotal bearing surface of means attached to said armature are all points in coplanar relationship to each other.

8. An electric contact controller, comprising, in combination, a base, an insulating means forming separate contact chambers on said base, a stationary contact disposed in each of the chambers, an electromagnet means mounted adjacent said insulating means, an armature having a movable contact carrier portion therewith shiftable linearly by said electromagnetic means, movable contacts with said carrier portion, a coil with said electromagnet means for which there is a rated voltage value, said coil upon energization exerting a force on said armature urging movement toward a contact seal position, contact springs inserted in openings of said contact carrier to exert a force effecting positive sealing engagement between each of the stationary and movable contacts, and toggle spring means attached between said armature and base for transmitting an increasing force progressively to said armature for movement toward fully open position of the contacts and a decreasing force to said armature continually for movement to a contact seal position such that summation of forces from said coil, said contact springs and said toggle spring means permits movement of said armature directly from fully open position to fully sealed position of contacts at a value of voltage between 50 and percent of rated coil voltage and reverse movement directly from fully sealed position to fully open position at a value of voltage below 50% of rated coil voltage.

9. The controller of claim 8 wherein said toggle spring means are in an assembly including a pair of wire springs unaffected by ambient temperatures, said pair of wire springs each having an intermediate coil portion having a longer leg extending from one end and a shorter leg extending from the other end, a transverse wire portion connecting the longer leg to a hook portion at one end, the short leg terminating in another hook portion which is formed coplanar with the shorter leg and is also coplanar with the hook portion of the longer leg, and bearing means with said base and said armature for engagement with minimum friction by said hook portions anywhere in a linear range of spring force between zero and greater force applicable in a negative rate toward contact fully sealed position.

References Cited in the file of this patent UNITED STATES PATENTS 2,304,972 Van Valkenburg et al. Dec. 15, 1942 2,308,475 Fawkes Jan. 12, 1943 2,580,418 Frese Jan. 1, 1952 2,647,743 Cook Aug. 4, 1953 2,782,278 Peters Feb. 19, 1957 2,814,689 Roche Nov. 26, 1957 2,831,938 Moyer Apr. 22, 1958 

